Cap



Dec. 10, 1968 A. R. RAusMG ETAL 3,415,405

CAP

Filed Oct. 27, 1966 F 1'9 .1 u. 48 2 M 1.1.

31. l 11 3b 43 P S 12 I 9 a \AS United States Patent 0 14,423/ 65 5Claims. (Cl. 215-48) ABSTRACT OF THE DISCLOSURE A bottle having aninwardly turned lip at its opening is provided with a tear-oif caphaving an outer tubular plug portion designed to sealingly engage saidlip and remain in the bottle opening, an inner tubular plug portionhaving a dome-shaped closed end attached to said outer tubular plugportion at a tear-off connection, and a slot extending upwardly betweensaid outer and inner tubular portions to said tear-off connection whichis sealingly closed when the cap is inserted into said bottle opening byinward deflection of said outer tubular portion and/or outwarddeflection of said inner tubular portion, the latter deflection beingpromoted by pressure within the bottle and/ or by a disc inserted intosaid inner tubular portion.

The present invention refers to a cap in combination with a containerhaving an inner over-pressure or sub-atmospheric pressure and whichcontainer is provided with an inwardly turned lip in the region of itsopening.

A cap of this kind has previously been suggested in the Belgian PatentNo. 666,263 granted July 30, 1965, and which corresponds to UnitedStates Patent No. 3,251,499. The container shown in this patent has, asis also the case according to the present invention, an inwardly turnedlip in the region of its opening. Further, the cap has a lid portion anda tubular plug portion, which on its end turned to the interior of thecontainer is provided with a flange in a way corresponding to apreferred embodiment of the present invention. The tightening of thecontainer is intended to be obtained by the pressure of engagementbetween a sharp edge of the lip and said flange.

So as to increase the tightness of the closing device still further ithas been proposed in Belgian Patent No. 678,159 granted Apr. 31, 1966,and which corresponds to United States Patent No. 3,317,070 to associatewith the tubular portion a sealing ring having a section in the form ofa triangle, which with sealing action is arranged to engage a surface ofthe inturned lip. Due to this provision one has been able to eliminateleakage, i.e. to prevent the gas from escaping between the cap and theinner surface of the container neck.

Preferably the cap is intended to be made of polythene or a similar kindof plastic material. As most gases have a certain ability of diffusingthrough polythene, as for example carbon dioxide, one always has toassume a certain loss of gas however effective the tightening means aremade. By tests one has discovered that a rather great portion of thediffusing gas passes through two small regions of the cap, which have areduced thickness. These regions are defined on one hand by the saidsealing ring, probably especially the apex portion of the sealing ring,and on the other hand by the region of an opening indication.

There is therefore a first object of the present invention to reduce thesaid diffusion at the same time as the virtues of the previouslyproposed constructions are maintained. Another object is to produce acap which is at least in some measure reclosable. These demands may besatisfied by a cap that includes the following combination:

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(a) a first tubular plug portion inserted into the container opening toa position of fixation;

(b) a second tubular plug portion on the inner side of the said firsttubular portion, said second portion in its upper part being connectedwith said first portion and in its lower part being provided with a lidportion closing the container opening;

(c) a narrow slot between the said first and second tubular portions,

(d) means for forcing the said first and second tubular portions into aneffective mutual pressure contact eliminating the breadth of the slotwithin an annular region.

Further features and advantages of the invention will be apparent fromthe following specification with reference to the accompanying drawings,in which FIG. 1 shows a section throgh a cap according to a firstpreferred embodiment of the invention;

FIG. 2 shows the same cap inserted into a container opening; and

FIG. 3 in a somewhat larger scale shows a portion of a cap according toa second preferred embodiment of the invention.

In FIGS. 1 and 2, 2 generally designates a cap having an axis A. The capconsists of two separable parts, namely an outer tubular plug portion 5intended to be fixed in the mouth of the container opening, see FIG. 2,and a part capable of being torn ofli and including the portions 3a, 3b,3c and 4. The connection between the two separable parts is designated12. To facilitate the tearing operation and to ensure that the tearingis carried out at the desired region a tearing indication is provided inthe form of a notch 11 in the connection 12. The notch 11 runs around ithe periphery of the connection 12.

The container which the cap is intended to close preferably consists ofa plastic bottle with a filling material which causes an innerover-pressure such as beer or other carbonated beverages. In FIG. 2 aportion of the container has been designated by 1. The cap is intended,in the preferred embodiment of the invention, to cooperate with theupper part of the container, i.e. the part nearest the opening which isdesigned in a special way. This is therefore included together with thecap in the closing device. FIG. 2 shows, how the upper part of thecontainer, hereinafter called the bottle, extends inwardly towards thecentre of the bottle opening and downwardly towards the interior of thebottle, so that a lip 6 is formed. To be able to take up existingstresses the lip 6 is designed] thicker than the rest of the bottlewall. 40 designates a reinforcement of the sealing part of the lip. Toprevent the cap from being damaged at the capping operation the part ofthe lip 6 against which sliding between the cap and the lip willpreferably take place is furthermore rounded. The rounding is designated41.

The sealing of the closing device occurs both between a point 7 on thelip 6 and a surface 23 of a flange 8 associated with the outer tubularpart 5, and above all between a sealing ring 30 of triangularcross-section on. the said tubular part 5 and a surface 20 of theinturned lip 6.

Of the remaining details shown in the figures a slot between the tubularpart 5 which is intended to be fixed in the bottle opening and the innertubular plug part 3b on the tear-off part of the cap has been designated43 and a depression at the end of the slot 43 in the region of thepulling handle 4 has been designated 34. The function of the depression34 and the function of a notch (not shown in the figures) provided inthe portion 30 and extending from the handle 4 towards the depression 34is to create a concentration of the pulling forces to a limited regionof the connection 12 at the initiation of the opening of the package.

In order that the stress in the connection 12 may not be too great atthe capping operation there has further been formed a ledge portion 44in the notch 11 and to reduce the necessary capping pressure a recess 45in the material has been provided. designates an annular flangeintended, together with the flange 8 to retain the tubular part 5 in thebottle mouth when the tear-off part of the cap is removed.

As has been mentioned in the introduction of the specification thediffusion of gas through the region 12 will be considerable if nothingis done to prevent it. According to the invention the diffusion isprevented by blocking the gas flow through the slot 43. This blocking isdone in connection with the capping operation by making the diameter ofthe tubular portion 312 such that the outer tubular portion 5 is pressedinwards into contact with the inner tubular portion 311. Thanks to thefact that the lip 6 is rather stiff, the deformation of the lip will beunimportant. Instead the main deformation will take place in the saidouter tubular portion 5. The deformation includes on one hand a generalradially directed compression and on the other hand a folding-in of thelower part of the tubular portion 5. The last phase of the cappingoperation takes place under the counter-action of pressure forcesbetween the annular portion 3c of the lid and the top of the bottle inthe region 13. When the cap has been inserted so far in the bottle neckthat the lower edge 7 of the lip 6 has snapped above the flange 8, theremaining deformation is so great that the space in the notch 43 atleast in the lower part thereof has been eliminated, and the tubularportion 3b, which is included in the tear-off part of the cap, is causedtightly to engage with its lower part the inner wall 47 of the tubularpart 5 fixed in the bottle neck. By this compression the necessaryinitial pressure between the sealing ring 30 and the surface is alsoobtained.

As earlier mentioned, the part which is intended to be torn off inconnection with the opening of the bottle consists of the portions 3a,3b, 3c and 4, the portions 312-0 forming a lid which is united with apulling handle 4. The lid consists of the central substantiallydome-shaped portion 3a and the annular portion and the tubulartransition portion 3b between the portions 3a and 3c. The centralportion 3a is, similarly as the cap as a whole, made from an elastic butyet relatively stiff material, such as HD- or MD-polyethylene. Theportion 3a and the tubular portion 3b further have a diameter which isof such size that when the tubular part 5 has been shrunk in connectionwith the capping, the ridge 46 will well engage the inner wall 47 of thepart 5. Furthermore, the portion 30 is slightly thicker in its centralpart so as to be substantially lens shape. The annular portion 30 isconnected to the pulling handle 4. The transition between the annularportion 30 and the tubular one 3b is designated 48.

If the interior of the bottle is subjected to an overpressure i.e. apressure greater than the surrounding atmosphere, the cap 2 will besubjected to a certain resilient deformation, which has been indicatedin FIG. 2 by dash lines. Under the influence of the axially directedcomponents of the pressure the dome-shaped central portion 3a of the capwill tend to be flattened. By this flattening action the diameter of thecentral portion will expand, whereby the engagement pressure between thesurfaces 46 and 47 increases. As the cap preferably is so shaped thatthe engagement region between the surfaces 46 and 47 and the apex of thetriangle 30 are in the same plane, designated B in FIG. 2 the increasedengagement pressure will be transferred directly via the material in thetubular part 5 to the triangular sealing ring 30. Hereby an upwardlydirected, axial pressure action is transformed into an outwardlydirected, radial one which highly increases the sealing action at thecircumferential edge of the sealing ring 30 and thanks to thecompression of the sealing ring, reduces the diffusion of gas throughsaid ring.

The lid of the cap, i.e. the part which has been defined by the portions3a-c and 4, may according to the preferred embodiment be reused forreclosing the bottle at least when not too great demands are made on thedurability and tightness of the closure. However, it could beestablished that the reclosing cap according to the present embodimentof the invention, such as it appears from the drawings, holds to anover-pressure as high as about 0.6 kp./cm. The reclosability may,however, be further improved, if the tubular portion 312 of the lid isconsiderably extended so as to pass beyond the lower edge of the part 5.Thereby an appreciable friction hold is obtained between the parts 3band 5 at the lower edge of the part 5.

In those cases where the bottle presents an inner subatmosphericpressure in relation to the surroundings, it is also possible accordingto the invention to modify the cap so that the central dome-shapedportion thereof will instead turn its convex surface outwards, wherebythe pressure difference in this case also may be utilized for thesealing.

The embodiment according to FIG. 3 differs from the cap according toFIGS. 1 and 2 substantially therein that the closure means also includesa disc 51, the diameter of which is somewhat greater than the innerdiameter of the lower portion 50 of the tubular portion 312 in the freestate of said portion, and which disc 51 is pressed into the center ofthe cap. The disc 51 is made of a stiff material, e. g. metal.Preferably, however, the disc consists of a piece that has been punchedout of the container opening in connection with the manufacture of thecontainer. Hereby no extra costs are involved for producing the discs.As should be apparent from the figure the disc acts upon the innertubular portion 3b so as on one hand to make the blocking of the passage43 more effective and on the other hand to increase the pressure betweenthe sealing ring and the bottle lip. In FIG. 3 the original shape of thelid portion 3a has been shown by dashed lines. In order to make theradical expansion possible without strongly stretching the lid material,the lid has, referring to the dashed lines, been made somewhatdome-shaped, however, not necessarily so pronouncedly cup-shaped as thelid portion 3a according to the previous embodiment.

We claim:

1. A tear-off cap type closure member for use with a container providedwith a pour opening having an inturned lip, said closure member beingmade from an elastic material and comprising an outer tubular plugportion which sealingly engages said lip and remains connected with saidcontainer, a removable inner tubular plug portion located within saidouter plug portion and having a closed inner end and which is joined tosaid outer plug portion by a relatively narrow annular tear-off portiontherebetween located at the outer ends of said plug portions, thetubular parts of said plug portions being initially spaced radially fromone another to establish a circular slot therebetween and the inner endof said slot being closed off by contact established between said innerand outer plug portions as said closure member is inserted into saidpour opening to effect engagement between said outer plug portion andsaid inturned lip.

2. A closure member for a container as defined in claim 1 wherein saidouter plug portion includes an integral sealing ring terminating in acircular edge which engages said inturned lip, said sealing ring beinglocated intermediate two spaced flanges which engage said inturned lipand serve to retain said outer plug portion connected to said inturnedlip when said inner plug portion is torn off.

3. A closure member for a container as defined in claim 1 wherein saidclosed end of said inner plug portion is dome-shaped, the convex side ofwhich faces in the direction presenting the higher gas pressure, theaxially directed force applied to said dome-shaped end as a result ofthe pressure differential existing on opposite sides thereof beingconverted by distortion of said dome-shaped end into an outwardlydirected radial pressure thereby to effect an increase in the sealingpressure between said outer plug portion and said inturned lip.

4. A closure member for a container as defined in claim 3 wherein saidouter plug portion includes an integral sealing ring terminating in acircular edge which engages said inturned lip, and wherein said circularsealing edge is located in the plane of pressure which is directedradially outward by said dilferential pressure induced distortion ofsaid dome-shaped inner end of said inner plug portion, said circularsealing edge being located intermediate two spaced flanges which engagesaid inturned \lip and serve to retain said outer plug portion connectedto said lip when said inner plug portion is torn off.

5. A closure member for a container as defined in claim 1 and whichfurther includes a relatively rigid disc pressed into said inner tubularplug portion and which exerts a References Cited UNITED STATES PATENTS3/1946 Moore 215-5l X 10/1966 Amesbury et al 220--24.5

10 DONALD F. NORTON, Primary Examiner.

U.S. Cl. X.R. 21552

